A New Insight into Application for Barley Chromosome Addition Lines of Common Wheat for Study on Metabolic Pathways

Barley has a much higher content of bioactive substances than wheat. In order to investigate additive and/or synergistic effect(s) on metabolites content of barley chromosomes, we used a series of barley chromosome addition lines of common wheat that were produced by a normal crossing. As an example, we adopted the phytosterol.  In determining the plant sterol levels in 2-week-old seedlings and dry seeds, we found that the level of stigmasterol in the barley chromosome 3 addition (3H) line in the seedlings was 1.5-fold higher than that in the original wheat line and in the other barley chromosome addition lines, but not in the seeds. Simultaneously, we determined the overall expression pattern of genes related to plant sterol biosynthesis in the seedlings of wheat and each addition line to assess the relative expression of each gene in the sterol pathway. Since we elucidated the CYP710A8 as a key character for the higher level of stigmasterol, full-length cDNAs of wheat and barley CYP710A8 genes were isolated. These CYP710A8 genes were mapped on chromosome 3 in barley (3H) and wheat (3A, 3B, and 3D), and the expression of CYP710A8 genes increased in the 3H addition line, indicating that is responsible for stigmasterol accumulation. Overexpression of the CYP710A8 genes in Arabidopsis increased the stigmasterol content but did not alter the total sterol level. Our results provide a new insight into the accumulation of bioactive compounds in common wheat, and a new approach for assessing plant metabolism profiles.